Adolescence is a time of substantial development within the brain, and emerging evidence shows the negative impact alcohol can have on the developing brain.
The developing brain
During adolescence the brain makes three major changes:
It refines its network of pathways by pruning the ones not being used;
It increases the amount of white matter on the nerves; and
It allows for new talents and lifelong interests to be developed (plasticity).
These changes prepare people for adulthood as the brain is more efficient, and able to perform more complex forms of thought and behaviour. Alcohol consumption may significantly impact the maturation of the adolescent brain.
The impact of alcohol on the developing brain
The emerging evidence is leading to increased concern regarding the impacts of alcohol on the developing brain.
The effects of substances such as alcohol are more permanent on the teenage brain. They have more harmful effects and can be more toxic to teens than in adults.
Compared with non-alcohol using teenagers, some alcohol using teenagers show significantly smaller brain volumes and lower density within the hippocampus and key prefrontal areas.
The hippocampus is responsible for memory and learning. Studies of adolescents show that heavy and extended alcohol use is associated with a 10% reduction in the size of the hippocampus. It also shows that the function of the hippocampus is uniquely sensitive to alcohol at this time and that alcohol may be poisonous to the nerve cells of the hippocampus causing them to be damaged or destroyed.
The prefrontal cortex is right at the front of the brain. The prefrontal cortex is proportionally much bigger in humans than in any other species, and it is involved in decision-making, planning and stopping yourself saying or doing something silly. It is also involved in social interaction, understanding other people and self-awareness. A paper investigating impulse-control ability found the reward response (controlled by the prefrontal cortex) differs in teenagers because of multiple changes occurring in the brain during adolescents. Impulse control can be influenced by alcohol consumption, and this influence is seen through to adulthood. When comparing prefrontal cortex volumes of adolescent heavy drinkers to non-drinkers, studies have found the prefrontal volumes to be smaller in heavy drinkers.
Alcohol acts on the nerve cells of the brain and disrupts the communication between nerves cells and other cells of the body. Alcohol suppresses the activities of certain nerve pathways, eventually making a person appear sluggish, lethargic and slow-moving. There is emerging evidence that heavy drinking during adolescence is associated with poorer cognitive functioning and possible brain response abnormalities while performing challenging cognitive tasks due to alcohol causing structural changes in the brain. It is thought this is due to alcohol causing structural changes in the brain.
More interesting information about the developing brain
Birth of the brain
We are born with twice as many neurons as we ever need in the brain. In next two to three years the neurons connect with each other to create a circuit in the brain – these neurons talk to each other via neurotransmitters. This is how messages are sent throughout your body so it functions correctly.
During infancy and childhood
During developing years children want to learn as many things they can. How their body moves, how to communicate, how to problem solve, how to use technology. Then it’s puberty.
The adolescent brain
Puberty sees the whole body change. And the brain changes too. The period of change within the brain lasts longer than the period of puberty, with brain maturation occurring until approximately 25 years of age.
During puberty, development in the brain occurs in stages. Changes to primary systems (such as motor and sensory) occurs in early adolescence as well as increase in brain volume. During later adolescence key changes in the prefrontal cortex (controls planning, judgement), the limbic system (controls emotion, emotional responses and hormone systems) and the corpus callosum (language) sees memory, planning, emotional regulation, decision-making and behavioural inhibition maturing into young adulthood.